Health Care Costs and Financing

Medicare beneficiaries whose prescription drug coverage improved with the introduction of Medicare Part D in 2006 were more likely to fill prescriptions for cholinesterase inhibitors or memantine, which are known to slow the progression of dementia, a new study reports. Dementia affects over 5 million people in the United States, including 1 in 8 adults at least 65 years old.

Although these antidementia drugs slow the rate of cognitive decline, they do not reverse the effects of the disease. This lack of reversal suggests that they are not effective in treating persons with advanced disease, even though up to 30 percent of the use of these medications is for nursing home residents with severe dementia.

The researchers compared the use of the antidementia drugs each year and the number of 30-day prescriptions filled for these drugs by persons age 65 or older continuously enrolled in a Medicare Advantage (managed care) plan from 2004 to 2007. They did the comparison by the type of pharmacy drug benefit enrolled in prior to Medicare Part D: no coverage, a quarterly benefit cap of $150, of $350, or no quarterly benefit cap (reference group).

After Part D went into effect, beneficiaries who previously had no coverage showed a 38 percent increase in the likelihood of using antidementia medication, relative to the no quarterly benefit cap ("no cap") group. All of the coverage groups significantly increased the number of filled 30-day antidementia drug prescriptions over the period of study. Among beneficiaries who filled prescriptions for antidementia drugs before Part D became effective, the "no coverage" group increased filling prescriptions by 36 percent and the "$350 cap" group showed a 15 percent increase.

The findings were based on pharmacy, inpatient, and outpatient medical claims data for patients in a Medicare Advantage plan offered by a large insurer in Pennsylvania. The study was funded in part by AHRQ (HS19461).

More details are in "The impact of Medicare prescription drug coverage on the use of antidementia drugs," by Nicole R. Fowler, Ph.D., M.H.S.A., Yi-Fan Chen, Ph.D., Christina A. Thurton, Ph.D., and others in the April 2013 BMC Geriatrics 13(37), 9 pp.